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Comments in Rich Text Documents

  • 6 minutes to read

The RichEditControl allows you to add comments to documents. You can add, edit, and remove comments in code and from the UI.

Create a Comment

Use the following API to attach a comment to a document range:

Member Description
Paragraph.Range Retrieves the paragraph’s range.
SubDocument.FindAll Finds all document ranges that contain the expression or text string.
SubDocument.Comments Provides access to the document’s Comment collection.
CommentCollection.Create Creates a new item in the CommentCollection.

The code snippet belows creates an empty comment associated with the following phrase: “an extensive problem in hardware and architecture is the construction of the emulation of checksums”.


View Example

// The target range is the specific phrase in the introduction's first paragraph
DocumentRange[] foundRanges = richEditControl.Document.FindAll("an extensive problem in hardware and architecture is the construction of the emulation of checksums", SearchOptions.None);
if (foundRanges.Length > 0)
    // Create a new comment
    Comment comment = richEditControl.Document.Comments.Create(foundRanges[0], "Johnson Alphonso D", new DateTime(2014, 4, 25));

Create a Nested Comment

The code snippet below demonstrates how to create a nested comment. To do that, pass the parent content as the CommentCollection.Create method’s parameter.


Document document = richEditControl.Document;

if (document.Comments.Count > 0)
    // Create a new comment nested to the second comment in the collection
    Comment nestedComment = document.Comments.Create("Brian Zetc", DateTime.Now, document.Comments[1]);

    // Add text to the newly created comment
    SubDocument nestedCommentDocument = nestedComment.BeginUpdate();
    DocumentRange textRange = nestedCommentDocument.InsertText(nestedCommentDocument.CreatePosition(0),
    "Suffix trees are comprehensively reviewed in Wikipedia");

Edit the Comment

Edit the Comment Content

Use the API from the table below to edit the comment’s content.

Member Description
Comment.BeginUpdate Opens the comment for modification.
SubDocument.InsertText Inserts a text string into the specified position.
TableCollection.Create Inserts a table into a document position.
ShapeCollection.InsertPicture Inserts a floating picture into the specified position position.
DocumentImageCollection.Insert Inserts an inline image in the specified position.
ShapeCollection.InsertTextBox Inserts a text box in the specified position.
Comment.EndUpdate Finalizes the comment update.

The following code sample adds text to the empty comment:


Document document = richEditControl.Document;

int commentCount = document.Comments.Count;
if (commentCount > 0)
    // The target comment is the first one
    Comment comment = document.Comments[0];
    if (comment != null)
        // Open the comment for modification
        SubDocument commentDocument = comment.BeginUpdate();

        // Add text to the comment range
            "J. Taylor, Enabling Voice - over - IP and RAID with sofa,  in Proceedings of NOSSDAV, Oct. 1994.\r\n" +
            @"R.Tarjan, S.Shenker, J.Gray, A.Einstein, Q.Thomas, and X.Sato, ""Deconstructing operating systems with flanchedripper"", in Proceedings of INFOCOM, Mar. 2000.");

        // End the comment update

Edit the Comment Attributes

Use the following members to change the comment parameters (author, date, etc.):

Member Description
Comment.BeginUpdate Opens the comment for editing.
Comment.Author Specifies the comment’s author.
Comment.Date Specifies the comment’s last modified date.
Comment.Name Specifies the comment’s name.
Comment.EndUpdate Finalizes the comment update.

The code snippet below changes the comment’s name, date and author.


Document document = richEditControl.Document;
int commentCount = document.Comments.Count;

if (commentCount > 0)

    // The target is the second last comment
    Comment comment = document.Comments[document.Comments.Count - 1];

    // Change the comment's name, author and creation date
    comment.Name = "Reference";
    comment.Date = DateTime.Now;
    comment.Author = "Vicars Annie";

Delete the Comment

To remove a comment from the document, use the CommentCollection.Remove method as shown in the code snippet below.

Document document = richEditControl.Document;
if (document.Comments.Count > 0)
   //Remove the fourth document comment

Comments in the User Interface

Users can use the Review Ribbon tab to insert, modify or remove comments. Refer to the How to: Create the RichEditControl with a Ribbon UI topic for more information on how to add the ribbon menu to the application.

The Comment group on the Review tab allows users to insert new comments, remove existing comments, and navigate through all the comments in the document.


The Tracking group buttons allow users to highlight comments in the document, to filter them by the author, and specify whether to display comments in the document margins or Reviewing Pane.


To add the Reviewing Pane to the RichEditControl, click the RichEditControl’s smart tag in the designer mode and select Create Reviewing Pane.



Set the RichEditControl’s DocumentCapabilitiesOptions.Comments property to Disabled to disable comments.

Display Options

The comments are displayed in the Reviewing Pane or in balloons that appear in the document margins. The related ranges are highlighted by a different color for each reviewer.


Use the CommentOptions‘s class properties to change the comment displaying options, such as range highlighting color or comment visibility. Access these properties via the richEditControl.Options.Annotations.Comments notation.


When you add a new comment, the CommentOptions.Visibility property set to Hidden changes its value to Visible.